Refrigeration expansion valve



May 26, 1942.

G. w. SMITH ETAL REFRIGERATION EXPANSION VALVE Filed Jan. 24, 1940 INVENTOR5 George .6111! BY do 6 A 60:11/1

ATTORNEY? Patented May 26, 1942 REFRIGERATION EXPANSION VALVE George W. Smith and James A. Smith, Lyons, N. Y., assignors to Kenmore Machine Products,

1110., Lyons, N. Y.

Application January 24, 1940, Serial No. 315,450

9 Claims.

This invention relates to novel and useful improvements in expansion valves for refrigeration systems, and it is particularly concerned with the devising of a valve which may be economically manufactured andwhich is highly effective under the various service conditions which may be encountered,

, In the customary refrigeration expansion valve which is subject to automatic control, flow of refrigerant from the inlet to discharge ports, through the valve seat, is regulated in part by the pressure on the discharge side of the valve which is transmitted to a pressure-responsive element working in opposition to the valve spring. The pressure-responsive elementitself may be manually adjusted by changing the loading of a spring applied thereto, or the pressure-responsive element loading may be modulated by superimposing a power element, or second pressure member in which the pressure changes are governed through the temperature existing in the expansion coil of the system. Again, the main valve spring may be made adjustable, so that the pressure differential between the main sprin and the force exerted through the pressureaesponsive element may be controlled within reasonable limits.

,While a number of such valves have been made commercially, there still remain for solution the problems of providing a valve which will not stick or bind, which will have a wider range of operation, to which the power element may be applied without danger of the action becoming erratic at the ends of the operating range, and which, withal, will not be unduly complicated or expensive. For example, one manifest difficulty with valves of this class has been the tendency of the valve needle to become canted or dislodged during operation, due to faulty pressure applications from both the main spring and the pressure pins.

As hereinafter more fully set forth,we propose to eliminate this trouble by providing a substantially frictionless but fully positive means for actuating the valve toward and away from its seat. As another example, some valves which function in a satisfactory manner over a limited high-temperature range become erratic when adjusted for low-temperature work, due to the formation of frost over the valve body which offsets the intended functioning of the power element. We propose to correct this defect in a simple manner by bringing the refrigerant through the valve in such fashion as to minimize the extreme temperature changes to which prior valves have been subject.

Various other objects and features of the invention will be apparent from a perusal of the following detailed description of a typical embodiment of an improved valve, reference being made throughout to the accompanying drawing, wherem:

Fig. 1 is a longitudinal section through a refrigerant expansion valve including a thermally actuated Dower element;

Fig. 2 is a section on the line 2-2 of Fig, 1, showing in clearer detail the path taken by the incoming refrigerant; and

Fig. 3 is a fragmentary side elevation of a further embodiment of the invention, portions thereof being drawn in section to show the sealing and locking means of the power element.

The valve comprises a main body member l0 formed on one side with an offset portion II to provide for the necessary inlet passages, and on one end with an extended cylindrical flange l2 adapted to receive a sealing bellows [3. A boss l4 formed on the main body II] in spaced relation to the inlet portion II is drilled and tapped to provide a discharge port l5. The main portion of the body is drilled from one end to the other with a centrally disposed longitudinal bore 16, which is counterbored on the flanged end to provide a shoulder I l, and which is internally threaded on the opposite end, as indicated by the reference numeral IE, to receive a closure member. The drilling of the main body in this manner eliminates an integral partition wall within the valve, as has heretofore been customary, and with it the necessity for complicated port and passage arrangements which have interfered with the free flow of the refrigerant, and have thus tended to reduce the valve capacity.

The offset portion H of the valve body is formed with a drilled and tapped passage 2| terminating in a recess 22, and which is closed by a fitting 23 which connects the valve to the receiver of the refrigeration system (not shown). The fitting 23 is also counterbored to receive a conical filter screen 24, the tip of which seats in the recess 22. This expedient serves to keep the filter from becoming distorted or loose, and thus assures the admission of clear refrigerant at all times. The inlet passage 2| communicates with the bore it of the main body through a diagonal drilled passage 25, which, as will be noted, if it is projected, clears the end of the flange portion l2. There are two noticeable advantages in providing an inlet passage of such angularity. The passage may be drilled from the exterior of the valve body without use of special tools or cross-drilling operations, and the refrigerant is brought into the valve body in a path of less frictional resistance, and therefore less energy loss in the refrigerant.

It will moreover be noted that the diagonal passage 25 communicates with the bore it above the shoulder ll, and that this enlarged portion of the bore is occupied by a cylindrical insert or plug 26, which, after being pressed into the bore, may be secured by solder, as indicated by the reference numeral 2?.

aligns itself with the passage 25. On the opposite side of the plug 26, the groove is drilled with a substantially radial duct 29, which in turn communicates with an axial passage 3i extending downward to within the chamber defined by the bore IE. Thus, refrigerant entering the passage 25 is caused to flow around the groove 28 in contact with the wall of the main body it, thence through the duct 29 and through the passage 3|,

before entering the discharge port l5. This construction provides a relatively warm zone oi liquid refrigerant within the main valve body which shields the sealing bellows and power element from the low temperature effects of the formed with diametrically opposed slots 34 which serve as keyways for lugs 35 formed on a springsupporting washer 36. This washer is threaded on a post 31 formed with a threaded enlarged portion disposed in the bore l5, and an adjustment portion extending through a central aperture in the cap 33. The cap 33 also receives a gland nut 33 for packing the projecting portion of the post El, and a cover cap 39 which protects the parts from accidental setting, thus making the bore I6 perfectly gas-tight. It will be apparent that, with these parts assembled as shown, the cap 39 may be removed and the projecting portion of the post 3'! turned with a wrench, thus causing the washer 35 to move lineally in the bore it. This motion is utilized to change the setting of the main valve spring,

' and hence the operating range of the valve.

Surrounding the threaded section of the post 31, and abutting the washer 3G, is a coiled spring 4!, which engages, at its opposite end, a valvesupporting washer 42 formed with a longitudinal bore 43 which is made conical or tapered at its lower end. A valve needle 45, of less diameter than the bore 43, is mounted within the bore 43, and the needle is formed with conical or tapered ends 46 and 41, the lower of which seats on the conical portion of the bore 43, while the upper end enters the valve seat 3| to close the refrigerant passage therethrough. The needle 45 is also formed with a shouldered portion 48 on which is disposed a washer 49, and through which movement of the needle, in response to movement of the sealing bellows l3, may be effected.

It will be particularly observed that the needle 45 may rock or tilt within the bore 43, or rather, with respect to the washer 42. Heretofore, difficulties in proper closing of needle valves have The plug 26 is formed externally with a circumferential groove 28 which been encountered, because of misalignments of the spring 4|. Byproviding a somewhat universal or adjustable seat' for the needle within the washer 42, any such misalignments are automatically compensated for, thus permitting the needle point 46 to enter the seat 3| correctly under all conditions of operation.

Further in accordance with the present invention, the connection between the sealing bellows i3 and the valve needle, and through which the opening and closing of the valve is made responsive automatically to the evaporator pressure, is effected in a positive manner. The bellows I3 is soldered within the cavity formed by the flange I2, and the bottom wall 5! of the bellows is drilled to receive the ends of three equi-angularly disposed push pins 52 which are soldered in place. The pins extend within the bore it through enlarged holes 53 formed longitudinally in the plug 26these holes also permitting the refrigerant pressure existing at the discharge port l5 to' act against the bellows I3 in the customary manner of automatic expansion valves.

Each pin 52 is drilled and tapped on its projecting end, as indicated by the reference numeral 54, to receive a screw 55 for supporting an annular washer 56 whose inner marginal portion overlaps the needle washer 49. It is of course apparent that, with the rocking bearing provided between the needle 45 and the cone washer 42, it would be inexpedient to have the pins 52 abut the cone end. Accordingly, the washer 46, which is in effect integral with the needle 45, is contacted by the washer 56, which in turn is actuated by the simultaneous movement of the three pins 52. The thrust of the pins thus acts through the plane surface of the washer 56 directly against the needle, and serves to maintain the needle in correct alignment with respect to the seat 3|. It will moreover be noted that the securing of the pins 52 to the bellows l3 and washer 56 prevents the pins from rubbing the walls of the holes. 53, thus eliminating a source of friction heretofore encountered.

When the valve is to be employed as a simple automatic valve, the flanged end I2 of the body is covered with a plain cap member and the bellows I3 is loaded with a spring. As herein illustrated, however, the valve is also provided with a thermally actuated power element for varying the loading in response to the temperature in the expansion coil. The flanged end 12 of the valve body is provided with external threads for engagement with internal threads 6! formed in a cap 52 having an internal shoulder 63. Apartition plate 64, formed with a flanged aperture 65, abuts the shoulder 63, and serves as a stop member for a coiled spring 66 whose opposite end presses against the bottom wall 5! of the sealing bellows l3. The cap 62 contains a power element bellows 61 in the form of a closed expansible casing which is soldered to the upper end of the cap 62, so that, as the power bellows expands and contracts, the lower wall 68 thereof moves lineally with respect to the valve body. A tube 69, passing through the cap 62, terminates in a bulb "H which may be located on the suction end of the evaporator, or other desired point, in accordance with usual practice. The tube and bellows is charged with a suitable refrigerant, such as methyl chloride, and as the temperature of the charging medium changes, the pressure within the bellows 61, and hence the force which it exerts, is proportionally modified.

The bottom walls 68 and 5| of the bellows 61 and 13 are automatically interconnected for conjoint movement when the cap 62 is screwed onto the body. The walls 68 and carry complementary fittings comprising threaded studs 12 and 13, which are interconnected by an internally threaded sleeve 15, which sleeve is formed of an insulating material. To effect the assembly, the threads for the studs and sleeve are made the same pitch as the threads for the cap 62 and flange 12. A bafiie plate 16 is also positioned on the pins 52 just below the lower wall 5|, to minimize admission of slugs of refrigerant to the bellows l3. It will also be seen that the stud 13 carries a flanged washer 14 in which is seated the spring 66.

To assemble the valve, the plug 26 is first tightly seated in the large end of the bore l6, with the duct 29 remote from the inlet passage 25. The sealing bellows l3, with the stud I3 and the pins 52 secured in the base thereof, and the baffle 16 positioned on the pins, is then dropped into position, with the free ends of the pins pass ing through the apertures 53 of the plug 26. Assembly of the valve parts may then be effected through the open end of the bor l6, and the cap 62, with the remaining parts of the bellows assembly, may be screwed into place in the manner just described.

It will be observed that the power bellows 61 and sealing bellows l3 are positively interconnected through the sleeve '15, and hence any motion of the power bellows is transmitted through the sealing bellows irrespective of the internal pressure conditions in the valve. The sealing bellows, in turn, is positively connected to the valve actuating washer 56, and therefore contractive, as well as expansive movements of the bellows are positively transmitted to the valve needle. While these parts are all interlinked for positive action, the motions, as applied to the needle 45, are substantially frictionless. As has heretofore been explained, this action is obtained without creating any tendency to bind the needle 45 with respect to its valve seat 3|.

Adjustment of the valve is normally effected through the post 3! to vary the loading on the spring 4|, and thereby the effective pressure differential between the spring and the variable force exerted by the power bellows 61. It may here be noted that the spring 66 may be replaced by a like spring of different rate to render the valve effective when used with various refrigerants without changing the refrigerant used to charge the power bellows. Likewise, some adjustment may be effected by rotating the cap 62, although for most service conditions, it is preferred to give the cap a fixed position with respect to the valve body, and then secure it in position by soldering.

In Fig. 3, the valve is slightly modified so that the cap 62a thereof may be utilized as a service adjustment to supplement the adjustment of the post 37, or, if desired, to act as a substitute therefor. In this embodiment, the power bellows 57a is not rigidly connected to the cap 62a, but rather it is provided with a shouldered and threaded stem 89 which projects loosely through the hole 8| in the cap. Washers 82 and 83 of insulating material are disposed on opposite sides of the hole, and the stem and the washers may be clamped tightly to the cap by a nut 84. The lower end of the cap 62a is formed with a circular seat portion 85 which receives an annular rubber gasket 86, which gasket may be clamped by a threaded lock ring 81 disposed on the external threads of the flanged end l2a of the valve body.

When the ring 81 is drawn up, the lower ex tremity of the cap is sealed against the entrance of air and moisture, which otherwise might enter the bellows chamber with damaging effects. The remainder of the structure may be similar to that of Fig. 1.

In adjusting the valve of Fig. 3, the nut 84 and ring 81 are loosened, and with the stem 80 held against movement, the cap 620. is rotated to vary the loading effect of the spring 66 to the desired degree. It will be observed that during this ad J'ustment the sleeve and stud connections between the bellows are unaffected, and the only reaction thereto is the extension or compression of the spring 66 and the power bellows 61. After this operation, the nut 84 and ring 81 are again tightened to lock and seal the assembly.

While we have described our invention with reference to several specific embodiments, it will be understood by those skilled in the art that numerous modifications may be resorted to without departing from the principles thereof, and accordingly it is not intended to limit the invention to the precise forms illustrated, but to encompass such combinations and parts as may be comprehended by the following claims.

We claim:

1. In a refrigerant expansion valve, a valve body formed with a valvereceiving portion, a cylindrical flange contiguous therewith and having a chamber formed therein, and an offset in let passage portion, said valve-receiving portion being formed with a longitudinal bore communicating with said chamber, a valve disposed in the bore, spring means for actuating the valve, and closure means for closing. the end of the bore and holding said spring and valve in operating position,.a discharge port formed in the valve body in communication with said bore, a separate insert disposed at the opposite end of the bore to divide the bore from said chamber, a sealing bellows secured within said chamber, a plurality of longitudinally disposed apertures formed in said insert, push pin members freely extending through said apertures and connecting said sealing bellows and said valve, a valve seat formed in said insert against which the valve may contact, a diagonal passage formed in the body and connecting said inlet passage portion and said bore at a portion thereof covered by said insert, said diagonal passage, as projected, extending beyond the end of said cylindrical flange, and a tortuous passage extending around said insert for connecting said diagonal passage and said valve seat.

2. In a refrigeration expansion valve, a valve body formed at one end with an extended cylindrical flange defining a sealing bellows chamber, a sealing bellows mounted in the chamber, a threaded stud secured to the bottom of the sealing bellows and projecting upwardly therefrom,

an internally threaded screw cap engaging the exterior of said cylindrical flange and covering said sealing bellows, a thermally actuated power element mountedwithin the cap and having an end wall movable with respect thereto, a threaded stud secured to said end wall and aligned with the stud secured to said sealing bellows, and a threaded sleeve connecting aid studs, the thread on said cap and the sleeve being of the same pitch whereby the cap may be applied and the bellows positively interconnected in one rotary operation.

3. A refrigeration expansion valve comprising a valve body having an extended end defined by a cylindrical flange, a chamber formed within said end a sealing bellows mounted within the chamber, an internally threaded cap engaging over said flange, said'cap containing a thermally actuated power element and a transversely disposed partition plate formed with a central aperture, threaded and aligned studs secured to the sealing bellows and the power element, a threaded sleeve interconnecting said studs and passing tively secured to said sealing bellows and ex-.

tending to within said valve body, said valve body being formed with a longitudinal bore, a cylindrical insert pressed into said bore at the end thereof adjacent said sealing bellows, said insert being formed with passages through which said pins freely extend, a valve seat in said insert, in let and outlet ports formed in said body and communicating with said bore on opposite sides of the valve seat, a circumferential groove in the insert in fluid communication with the inlet port, a passage in the insert connecting said groove and seat at a point remote from the inlet port, a valve needle in the bore for engagement with the seat, a circular plate connected to the ends 01' the push pins and formed-with a central aperture through which the needle extends in abutting relation, spring means for urging the needle toward its seat, and closure means for the opposite end of the bore for maintaining the spring under compression.

4:. In a thermostatic expansion valve including a body having a sealing bellows affixed thereto, a threaded cap adapted to be screwed onto the body to enclose the sealing bellows, a power bellows disposed within the cap, a rigid connection between the two bellows, a stem on the power bellows extending through the cap, means sealing and locking the stem to the cap, said means being releasable to permit adjustment of the cap,

resilient means associated with the bellows as, r sembly and operatively engaged for adjustment by the cap, and releasable gasket means for sealing the connection between the cap and body.

5. A refrigeration expansion valve comprising a body formed with a longitudinal bore extend ing therethrough, said body being formed on one end with an outwardly flanged portion in communication with the bore, a sealing bellows mounted in the flanged portion and extending toward said bore, a shoulder formed in the bore,

adjacent the inner end of the bellows, a separate insert plug snugly mounted in the bore and abutting the shoulder, said plug having a circumferential groove, a radial passage communicating with the groove, and an axial passage extending,

from one end face of the plug to said radial passage, said plug being also formed with longitudinal and circumferentially spaced independent clearance holes, an inlet port formed in the body and communicating with said circumferposite end of the body for closing the bore and holding the resilient means, a thrust plate encircling the valve, and push pins extending through the spaced circumferential clearance holes in the plug and each engaging the sealing bellows on one end'and the thrust plate on the other end, said circumferential clearance holes being of greater diameter than the pins to provide for free movement and for fluid communication between the bellows and flange portion of the body and the discharge port.

6.-A refrigerant expansion valve comprising a' body formed with a longitudinal bore terminating at one end in a flanged portion of the body, a sealing bellows mounted in said flanged portion, inlet and outlet ports formed in the body in spaced relation, a plug disposed in the body between the flanged portion and the bore, a valve seat formed in the plug below the flanged portion, a fluid passage formed in the plug between the inlet and outlet ports of the body and extending through said seat, said plug being formed with a plurality of circumferentially spaced, longitudinally disposed apertures, push pins fixedly secured at one end to the sealing bellows and freely extending through the apertures, an annular plate disposed in the body below the plug and fixedly secured to the opposite ends of the pins, a valve for the valve seat, said valve extending freely through the plate, shoulder means on the valve for engagement with the plate, a cup member formed with a bore in which said needle is mounted, said needle being of less diameter than the cup bore and formed with a tapered end engaging in said bore to provide a free rocking bearing for the needle, and spring means disposed in the bore and engaging the cup member to urge the needle towards its seat.

'7. A refrigerant expansion valve comprising a body formed with a longitudinal bore, said body having a flanged portion at one end, a sealing bellows secured to said flanged portion, a transverse wall member positioned in the body and the bore to separate the sealing bellows from the bore, a valve seat in the wall member, a plurality of circumferentially spaced clearance holes formed in the wall member in spaced relation to the valve seat, a plurality of push pins securely fixed to the sealing bellows and each extending through one of the clearance holes, said pins being of less diameter than the holes, inlet and outlet ports formed in the body and communicating with each other through the seat, said outlet port being in fluid communication with the bore below the wall and with the sealing bellows through said clearance holes, a plate secured to the ends of the push pins extending through the wall, said sealing bellows, pins, and plate thereby being integrated into a substantially rigid and unitarily movable assembly, a valve needle in the bore below the seat, a spring for pressing the needle towards its seat, closure means for the bore for retaining the spring in the bore and against the needle, and a rocking bearing connection between the plate and the needle, whereby the needle may adjust itself to the seat concurrently with lineal movement only of the integrated assembly of bellows, pins, and plate.

8. The structure of the preceding claim '7, wherein the flanged portion of the body is provided with a cap, a power bellows in the cap, and a fixed connection extending between the sealing bellows and the power bellows.

9. A thermostatic expansion valve comprising a body having a sealing bellows affixed thereto, a cap for the body, said cap having a power bellows disposed therein, said cap and said body being formed with means for connecting the cap to the body whereby the sealing bellows is enclosed when the cap and body are connected through said means, connection fittings on both the sea-ling bellows and the power bellows, said connection fittings including means adapted to interengage each other to connect said bellows concurrently with the connecting of the cap to the body.

GEORGE W. SMITH. JAMES A. SMITH. 

